Camera system

ABSTRACT

To improve user-friendliness when checking the depth of field, in a camera system having an aperture value alteration function. A camera system ( 100 ) has an imaging optical system (L), an imaging unit ( 45 ), an aperture adjustment unit ( 29 ), a liquid crystal display monitor ( 16 ), and an AGC unit ( 59 ) of an analog signal processing unit ( 51 ). The imaging optical system (L) forms an optical image of a subject. The imaging unit ( 45 ) converts the optical image into an image signal, and obtains an image of the subject. The aperture adjustment unit ( 29 ) can adjust the aperture value of the imaging optical system. The liquid crystal display monitor ( 16 ) displays the image. The AGC unit ( 59 ) adjusts the brightness of the image displayed on the liquid crystal display monitor ( 16 ) according to the aperture value.

TECHNICAL FIELD

The present invention relates to a camera system, and in particular,relates to a camera system used in a digital camera having an aperturevalue alteration function.

BACKGROUND ART

Single-lens reflex digital cameras have been rapidly growing inpopularity in recent years. With this single-lens reflex digital camera,when observing a subject using an optical viewfinder, the light (or theimage of the subject) incident on an imaging optical system is reflectedby a reflecting mirror arranged on the optical path, and guided to aviewfinder optical system. As a result, the subject image is convertedinto an erected image by a pentaprism and the like, and guided to theoptical viewfinder. Therefore, a user can observe the subject imageformed by the image optical system from the optical viewfinder.

On the other hand, when the imaging optical system is used forphotographing, the reflecting mirror is retracted from the photographingoptical path. As a result, the viewfinder optical path is switched tothe photographing optical path, and the reflecting mirror returns to afixed position immediately when photographing ends. This system is thesame for a conventional silver halide camera or a digital camera, if itis a single-lens reflex system.

However, photographing using an optical viewfinder is extremelydifficult for a beginner who is inexperienced with photographing using adigital camera.

Consequently, a camera system having a monitor photographing mode inwhich it is possible to observe a subject using a liquid crystal displaymonitor when photographing has been proposed (for example, refer toPatent Document 1).

Patent Document 1: Japanese published unexamined applicationJP2001-125173

DISCLOSURE OF INVENTION

Normally, this kind of camera system has an aperture value alternationfunction. In the case of the monitor photographing mode, real-timeimages captured sequentially with the set aperture values are displayedon a display device. Therefore, it is possible to check the depths offield which change according to the aperture value, via the displaydevice.

However, normally, the amount of light incident on the imaging sensorlessens if the aperture value becomes large, and the image displayed onthe display device becomes dark. As a result, sometimes it is difficultto check the depth of field with some of the aperture values.

A challenge of the present invention is to improve the convenience atthe time of checking the depth of field, in a camera system having theaperture value alteration function.

A camera system according to a first aspect of the present invention isa camera system for photographing a subject, and includes an imagingoptical system, an imaging unit, an aperture adjustment unit, a displayunit, and an image adjustment unit. The imaging optical system forms anoptical image of the subject. The imaging unit converts the opticalimage into an image signal, and obtains an image of the subject. Theaperture adjustment unit can adjust an aperture value of the imagingoptical system. The display unit displays the image. The imageadjustment unit adjusts the brightness of the image displayed on thedisplay unit according to the aperture value.

In this camera system, when the aperture value is changed, thebrightness of the image is adjusted by an image adjustment unitaccording to the aperture value. As a result, regardless of the aperturevalue, the brightness of the image displayed can be kept to a degreewhich verification can be done easily. By doing so, in this camerasystem, the user can easily check the depths of field of images, withoutbeing affected by the difference in the brightness of images due to thedifference in the aperture values.

A camera system according to a second aspect of the present invention isthe camera system of the first aspect, wherein the image adjustment unitamplifies the image signal according to the aperture value.

A camera system according to a third aspect of the present invention isthe camera system of the second aspect, wherein the image adjustmentunit amplifies the image signal based on information on the relationshipbetween the aperture value and the amplification factor of the imagesignal.

A camera system according to a fourth aspect of the present invention isthe camera system of the third aspect, further including an aperturevalue input unit to which the aperture value can be input. The displayunit can display a standard image and a comparative image side by side.The standard image is an image obtained with a standard aperture valueset in advance in the control unit. The comparative image is an imageobtained with a set aperture value set in the aperture value input unit.

A camera system according to a fifth aspect of the present invention isthe camera system of the fourth aspect, further including an operationunit to which information can be input from the outside, and an imagerecording unit for recording the image. The standard image andcomparative image are recorded in the image recording unit based oninformation inputted from the operation unit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall configuration diagram of a camera system;

FIG. 2 is a block diagram showing the control system of a camera body;

FIG. 3 is a block diagram showing the control system of aninterchangeable lens;

FIG. 4 is a top view of the camera system;

FIG. 5 is a rear side elevation of the camera system;

FIG. 6A is a an expansion plan of an aperture ring looked from theoutside in the radial direction, and FIG. 6B is an expansion plan of theaperture ring looked from the inner side in the radial direction;

FIG. 7 is a section view showing the joining portion of the aperturering and an aperture linear sensor;

FIG. 8 is a circuit configuration diagram of the aperture linear sensor;

FIG. 9 is a graph showing the relationship between the position of awiper relative to the aperture ring and the output value of the aperturelinear sensor;

FIG. 10 is a diagram for describing a viewfinder photographing mode;

FIG. 11 is a diagram for describing a monitor photographing mode;

FIG. 12 is a flowchart of a depth of field reviewing mode;

FIG. 13A and FIG. 13B are examples of images displayed on a liquidcrystal display monitor;

FIG. 14 is a flowchart of a depth of field reviewing mode (secondembodiment);

FIG. 15 is a flowchart of the depth of field reviewing mode (secondembodiment);

FIG. 16 is an example of an image displayed on the liquid crystaldisplay monitor (second embodiment); and

FIG. 17 is an example of an image displayed on the liquid crystaldisplay monitor (other embodiment)

EXPLANATION OF REFERENCE

-   L Imaging optical system-   Df Defocus amount-   X Optical path-   1 Camera body-   2 Interchangeable lens unit-   4 Quick return mirror-   9 Viewfinder eyepiece window-   10 Shutter unit-   11 Imaging sensor (Imaging unit)-   12 Body microcomputer-   14 Shutter control unit-   15 Image displaying control unit-   16 Liquid crystal display monitor (Display unit)-   18 Image recording unit-   20 Lens microcomputer-   21 Lens mount-   23 Body mount-   25 Focus lens group-   27 Aperture control unit-   28 Aperture unit-   28 b Aperture drive motor-   29 Aperture adjustment unit-   30 Release button-   31 Shutter speed setting dial-   33 Index-   38 Zoom ring-   39 Focus ring-   40 Aperture ring (Aperture value setting unit)-   41 Aperture linear sensor-   43 Quick return mirror control unit-   44 Quick return mirror drive motor-   51 Analog signal processing unit 51-   59 AGC unit (Image adjustment unit)-   62 Zoom control unit-   65 Focus drive motor-   69 Interchangeable lens internal memory-   71 Photographing/regenerating mode switching lever-   72 MENU button-   75 Photographing mode switching button-   76 Depth of field reviewing mode button

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below whilereferring to the figures.

First Embodiment 1: Overall Configuration of the Camera System

A camera system 100 as one embodiment of the present invention will bedescribed using FIGS. 1 to 3. FIG. 1 is an overall configuration diagramof the camera system 100. FIG. 2 is a control block diagram of a camerabody 1. FIG. 3 is a control block diagram of an interchangeable lensunit 2.

The camera system 100 is a system used in a single-lens reflex digitalcamera of the interchangeable lens type. As shown in FIG. 1, the camerasystem 100 mainly includes a camera body 1, and an interchangeable lensunit 2 mounted on the camera body 1 and is removable. Theinterchangeable lens unit 2 forms an optical image of a subject. Thecamera body 1 converts the optical image formed by the interchangeablelens unit 2 into an electrical signal, and performs the recording ofimage data, displaying of an image, and the like.

1.1: Interchangeable Lens Unit

As shown in FIGS. 1 and 3, the interchangeable lens unit 2 mainlyincludes an imaging optical system L, a zoom adjustment unit 24 whichadjusts the zoom magnifying power of the imaging optical system L, afocus adjustment unit 22 which adjusts the focus of the imaging opticalsystem L, an aperture adjustment unit 29 which adjusts the aperturevalue (the actual F value which changes according to the opening degreeof the aperture) of the imaging optical system L, and a lensmicrocomputer 20 as a lens control portion. The imaging optical system Lconnects a subject image to an imaging sensor 11 of the camera body 1.

The lens microcomputer 20 is a unit for controlling various sequences ofthe interchangeable lens unit 2. Various lens information regarding theinterchangeable lens unit 2 are stored in the lens microcomputer 20. Thelens microcomputer 20 can communicate both ways with a zoom control unit62, a focus control unit 26, and an aperture control unit 27.

As shown in FIGS. 1 and 3, the zoom adjustment unit 24 mainly includes azoom linear sensor 60, an A/D converter 61, and a zoom control unit 62.The zoom control unit 62 can receive signals from the zoom linear sensor60 via the A/D converter 61. The zoom control unit 62 converts therotational angle of a zoom ring 38 detected by the zoom linear sensor 60into focal length information of the imaging optical system L. The zoomcontrol unit 62 sends the focal length information to the lensmicrocomputer 20.

As shown in FIGS. 1 and 3, the focus adjustment unit 22 mainly includesa focus lens group 25, and a focus control unit 26 which controls theoperation of the focus lens group 25. The focus control unit 26 canreceive signals from the focus linear sensor 63, and can send thesignals to a focus drive motor 65 via the A/D converter 64. The focuslinear sensor 63 detects the rotational angle of a focus ring 39. TheA/D converter 64 digitalizes the rotational angle information detectedby the focus linear sensor 63. The focus control unit 26 converts therotational angle information of the focus ring 39 digitalized by the A/Dconverter 64 into object point distance information. The focus controlunit 26 sends the object point distance information to the lensmicrocomputer 20 based on a command from the lens microcomputer 20. Thefocus control unit 26 drives the focus drive motor 65 based on a controlsignal from the lens microcomputer 20. In this way, focus adjustment isperformed by the focus adjustment unit 22.

The aperture adjustment unit 29 mainly includes an aperture unit 28, anaperture control unit 27 which controls the operation of the apertureunit 28, and an aperture ring 40 for setting an aperture value. Theaperture unit 28 includes an aperture blade not shown in the figure, andan aperture drive motor 28 b for driving the aperture blade.

The aperture control unit 27 detects the aperture value set by theaperture ring 40. More specifically, the aperture linear sensor 41 shownin FIG. 3 detects the rotational angle of the aperture ring 40. The A/Dconverter 67 digitalizes the rotational angle detected by the aperturering 40. The aperture control unit 27 can receive signals from theaperture linear sensor 41 via the A/D converter 67, and converts therotational angle information of the aperture ring 40 digitalized by theA/D converter 67 into aperture value information.

The aperture control unit 27 sends the aperture value information to thelens microcomputer 20 based on a command from the lens microcomputer 20,and drives the aperture drive motor 28 b based on a control signal fromthe lens microcomputer 20. The aperture drive motor 28 b drives theaperture blade according to the aperture value set at the aperture ring40, according to the control signal from the aperture control unit 27.In this way, the aperture value of the imaging optical system L isadjusted by the aperture adjustment unit 29.

The interchangeable lens unit 2 further includes a lens mount 21, and isdetachably mounted on a body mount 23 arranged in front of the camerabody 1 via the lens mount 21. The interchangeable lens unit 2 includesan electrical segment, not shown in the figure, arranged on the lensmount 21. The camera body 1 includes an electrical segment, not shown inthe figure, arranged on the body mount 23. The transmitting andreceiving of lens information and various control signals are performedbetween the body microcomputer 12, which will be described later, andthe lens microcomputer 20 via these electrical segments.

1.2: Camera Body

As shown in FIGS. 1 and 2, the camera body 1 mainly includes a quickreturn mirror 4, a viewfinder optical system 19, a focus detection unit5, a shutter unit 10, an imaging unit 45, and a body microcomputer 12 asthe body control unit. The body microcomputer 12 controls varioussequences. For example, a phase difference detection system is adoptedas the focus detection system of the focus detection unit 5.

As shown in FIGS. 1 and 2, a quick return mirror control unit 43 and aquick return mirror drive motor 44 are arranged for driving the quickreturn mirror 4. The quick return mirror control unit 43 drives thequick return mirror drive motor 44 based on a control signal from thebody microcomputer 12. A shutter control unit 14 and a shutter drivemotor 10 a are arranged for driving the shutter unit 10. The shuttercontrol unit 14 drives the shutter drive motor 10 a (not shown in thefigure) based on a control signal from the body microcomputer 12. Thebody microcomputer 12 can send signals to the shutter control unit 14and the quick return mirror control unit 43.

The imaging unit 45 mainly includes an imaging sensor 11, and an imagingsensor control unit 13 which controls the operation of the imagingsensor 11. The imaging sensor 11 is, for example, a CCD (Charge CoupledDevice), and the like. The imaging sensor 11 converts the optical imageformed by the imaging optical system L of the interchangeable lens unit2 into an image signal.

As shown in FIG. 2, the image signal outputted from the imaging sensor11 is processed in order by an analog signal processing unit 51, an A/Dconverter 52, a digital signal processing unit 53, a buffer memory 54,and an image compressing unit 56. More specifically, the image signal issent from the imaging sensor 11 to the analog signal processing unit 51.The analog signal processing unit 51 performs an analog signalprocessing such as gamma processing and the like on the image signaloutputted from the imaging sensor 11.

An AGC (Auto Gain Control) unit 59 which corrects the level (Gain) ofthe analog image signal as the image adjustment unit is included in theanalog signal processing unit 51. This AGC unit 59 has an amp functionwhich compensates the level insufficiency of the image signal, in thecase that proper exposure cannot be obtained in the depth of fieldreviewing mode which will be described later, and the like. In this ampfunction, the analog image signal is amplified by a proper amplificationfactor according to the set aperture value, so as to meet within theinput voltage range of the A/D converter 52 which will be describedlater. For example, this analog signal processing unit 51 performsprocessing and the like which changes the gain on the actual apertureimage captured in the depth of field reviewing mode which will bedescribed later, using the AGC unit 59, so that the image displayed onthe liquid crystal display monitor 16 which will be described later willhave an optimum brightness. As a result, even in the case that theaperture value is large, the image shown on the liquid crystal displaymonitor 16 becomes bright, and it becomes easy to observe the actualaperture image.

The image signal with the analog signal processing performed thereon issent to the A/D converter 52 from the analog signal processing unit 51.The A/D converter 52 converts the analog image signal outputted from theanalog signal processing unit 51 into a digital signal.

The digital signal processing unit 53 performs a digital signalprocessing such as denoising, edge enhancement, and the like, on theimage signal converted into a digital signal by the A/D converter 52.The image signal with the digital signal processing performed thereon issent to the buffer memory 54 from the digital signal processing unit 53.The buffer memory 54 once stores the image signal processed by thedigital signal processing unit 53. The buffer memory 54 is, for example,a RAM (Random Access Memory), and the like.

The image signal stored in the buffer memory 54 is sent to the imagecompressing unit 56 from the buffer memory 54 according to a commandfrom an image recording control unit 17. The image compressing unit 56performs a compressing processing on the image signal according to acommand from the image recording control unit 17. Through thiscompressing processing, the data size of the image signal becomessmaller than the data size of the original image signal. The JPEG (JointPhotographic Experts Group) method and the like, for example, is used asthe compressing method. The compressed image data is sent to an imagerecording unit 18 and the liquid crystal display monitor 16 from theimage compressing unit 56.

The image recording control unit 17 and the image recording unit 18 arearranged in order to record the image signal. The image recordingcontrol unit 17 controls the image recording unit 18 to read and writethe image data on, for example, a card type recording media, not shownin the figure. More specifically, the image recording control unit 17controls the image recording unit 18 based on a control signal from thebody microcomputer 12. The image recording unit 18 records the imagedata in an internal memory and/or a recording media, based on thecommand from the image recording control unit 17. The information storedwith the image data is, for example, the time and date when the image iscaptured, the focal length information, shutter speed information,aperture value information, photographing mode information, and thelike.

An image displaying portion 46 and the liquid crystal display monitor 16are arranged in order to display the image of a subject. An imagedisplaying control unit 15 controls the liquid crystal display monitor16 based on a control signal from the body microcomputer 12. Morespecifically, the image displaying control unit 15 reads the image dataobtained by the imaging sensor 11, and displays the image on the liquidcrystal display monitor 16 after a predetermined process is performed onthe image data. The liquid crystal display monitor 16 displays variousinformation, and along with it, displays the image signal as a visibleimage, based on the command from the image displaying control unit 15.The information displayed includes, for example, focal lengthinformation, shutter speed information, aperture value information,photographing mode information, focused state information, whether ornot there is an aperture ring 40 of the interchangeable lens unit 2, asetting step and the set width of the aperture value, and the like. Inaddition, the liquid crystal display monitor 16 displays a settingscreen to be set by the user, in a predetermined photographing andregenerating mode, based on a command of the image displaying controlunit 15.

The body microcomputer 12 can communicate both ways with the imagerecording control unit 17, the image displaying control unit 15, and thedigital signal processing unit 53. The body microcomputer 12 includes amemory 68 which stores various information and signals.

1.3: Operation portions

Here, the operation portions of the camera system 100 will be describedusing FIGS. 4 and 5. FIG. 4 is a top view of the camera system 100. FIG.5 is a rear view of the camera body 1.

As shown in FIG. 4, a release button 30 and a shutter speed setting dial31 are arranged on the camera body 1. The release button 30 and theshutter speed setting dial 31 are arranged on the top surface of thecamera body 1.

The release button 30 sends the operation timing of the shutter to thebody microcomputer 12. The shutter speed setting dial 31 is an operationmember for setting the shutter speed. The shutter speed setting dial 31sends the set shutter speed information and shutter mode information. Itis possible to adjust the shutter speed by rotating the shutter speedsetting dial 31. The shutter speed setting dial 31 has an automaticposition in which the shutter speed is automatically set.

As shown in FIG. 4, a filter mount 37 is arranged on the subject side ofthe interchangeable lens unit 2. A zoom ring 38, a focus ring 39, andthe aperture ring 40 are arranged in order toward the camera body 1 side(the Z axis direction negative side) from the filter mount 37, on theinterchangeable lens unit 2. The zoom ring 38, the focus ring 39, andthe aperture ring 40 are all cylindrical rotational operation membersarranged rotatably on the outer circumferential surface of theinterchangeable lens unit 2. The aperture ring 40 is an example of anaperture value setting portion.

As shown in FIG. 5, a power button 70, a photographing/regenerating modeswitching lever 71, a MENU button 72, a cross-shape operation key 73, aSET button 74, and a depth of field reviewing mode button 76 arearranged on the rear surface of the camera body 1. The liquid crystaldisplay monitor 16 is arranged on the rear surface (surface on the userside, surface on the Z axis direction negative side) of the camera body1.

The power button 70 is a member which is operated to perform the ON/OFFof the power of the camera system 100. The photographing/regeneratingmode switching lever 71 is a member which is operated to switch betweena photographing mode and a regenerating mode. Here, the photographingmode is a mode in the camera system 100 for newly taking a picture of asubject and turning it into an image signal. The regenerating mode is amode in the camera system 100 for displaying an image data which hasalready been photographed and stored.

When the user photographs, the power button 70 is switched to ON, andthe photographing/regenerating mode switching lever 71 is switched tothe photographing mode. By doing so, the power of the camera system 100is turned on, and the visible image of a subject converted into anelectrical image signal by the imaging sensor 11 is displayed on theliquid crystal display monitor 16 based on a command from the imagedisplaying control unit 15.

The MENU button 72 is a member which is operated for displaying variousoperation menus on the liquid crystal display monitor 16. When the userpresses the MENU button 72 in the state which the camera system 100 isin the photographing mode, a setting menu screen is displayed on theliquid crystal display monitor 16 based on the command of the imagedisplaying control unit 15. On the setting menu screen, icons of settingitems which can be changed by the user in the photographing mode aredisplayed.

The cross-shaped operation key 73 is a member which is operated forselecting a displayed item on the various operation menus, and itincludes up and down, and left and right arrow keys. The SET button 74is a member which is operated for deciding on a displayed item on thevarious operation menus. The depth of field reviewing mode button 76 isa button for changing into a depth of field reviewing mode which will bedescribed later.

In addition, the body microcomputer 12 can receive signals from therelease button 30, the shutter speed setting dial 31, thephotographing/regenerating mode switching lever 71, the MENU button 72,the cross-shaped operation key 73, the SET button 74, a photographingmode switching button 75, and the depth of field reviewing mode button76.

1.4: Aperture Ring

Here, the aperture ring 40 will be described using FIGS. 6A to 9. FIG.6A is an expansion plan of the aperture ring 40 looked from the outsidein the radial direction, and FIG. 6B is an expansion plan of theaperture ring looked from the inner side in the radial direction. FIG. 7is a section view of the joining portion of the aperture ring 40 and anaperture linear sensor 41. FIG. 8 is a circuit configuration diagram ofthe aperture linear sensor 41. FIG. 9 is a graph which shows therelationship between the rotational angles of the aperture ring 40 andthe output values of the aperture linear sensor 41.

As shown in FIG. 6A, aperture values are shown on the outercircumferential surface of the aperture ring 40. The display region ofthe aperture values is divided into two regions. More specifically, asshown in FIG. 6B, the displaying portion of every 1 AV (Aperture Value)from “2” to “11” corresponds to the manual mode. As shown in FIG. 6A,the displaying portion “A” corresponds to the automatic mode. As shownin FIG. 6B, on the inner circumferential portion of the aperture ring40, a linear cam groove 42 is formed.

As shown in FIG. 7, the aperture linear sensor 41 has a cylindricalshaped wiper 41 a which protrudes out in the radius direction of theaperture ring 40. As shown in FIGS. 6 b and 7, the wiper 41 a of theaperture linear sensor 41 is inserted into the cam groove 42 formed onthe aperture ring 40. If the aperture ring 40 rotates, the wiper 41 amoves in the direction (Z axis direction) along the optical axis alongthe cam groove 42.

As shown in FIG. 8, the aperture linear sensor 41 is made up of by acircuit which has a variable resistor. The terminal T2 shown in FIG. 8is connected to the wiper 41 a, and the terminals T2 and T3 areconnected to two end portions 41 b and 41 c of the aperture linearsensor shown in FIG. 7. A predetermined voltage is applied between theterminals Ti and T3. By the sliding of the wiper 41 a on amagnetoresistive element in the interior of the aperture linear sensor41, the output (output voltage) of terminal T2 changes to be linear.

As shown in FIGS. 6A and 6B, if the position where the character “2” onthe aperture ring 40 is shown matches the position of an index 33, thewiper 41 a of the aperture linear sensor 41 is on the position P on thecam groove 42. In this case, as shown in FIG. 9, the output value(output voltage value) of the aperture linear sensor 41 becomes P′. Inother words, the output voltage value of the aperture linear sensor 41,when the position of the character “2” on the aperture ring 40 shown ismatched with the position of the index 33, becomes P′.

Likewise, when the positions where the characters “2.8”, “4”, “5.6”,“8”, “11”, and “A” on the aperture ring 40 shown are matched with theposition of the index 33, by rotating the aperture ring 40, the wiper 41a of the aperture linear sensor 41 is on positions Q, R, S, T, U, and Vof the cam groove 42. In that case, the output value (output voltagevalue) of the aperture linear sensor 41 becomes Q′, R′, S′, T′, U′, andV′, respectively. In other words, the output voltage value of theaperture linear sensor 41 becomes Q′, R′, S′, T′, U′, and V′, when thepositions where the characters “2.8”, “4”, “5.6”, “8”, “11”, and “A” areshown on the aperture ring 40 are matched with the position of the index33.

In this way, the aperture linear sensor 41 has an output (output voltagevalue) which corresponds one on one to the rotational angle of theaperture ring 40. An aperture value signal according to the rotationalangle of the aperture ring 40 is outputted as the voltage change.Therefore, based on the output from the aperture linear sensor 41, it ispossible to detect the rotational angle of the aperture ring 40.

2: Operation of the Camera System

The operation of the camera system 100 will be described using FIGS. 10and 11. FIG. 10 is a diagram for describing the viewfinder photographingmode. FIG. 11 is a diagram for describing the monitor photographingmode.

This camera system 100 has two photographing modes. One photographingmode is the viewfinder photographing mode in which a user photographswhile observing the viewfinder eyepiece window 9, and it is the normalphotographing mode in a conventional single-lens reflex camera. Theother photographing mode is the monitor photographing mode in which theliquid crystal display monitor 16 is used to photograph.

2.1: Viewfinder Photographing Mode

As shown in FIG. 10, in the viewfinder photographing mode, the quickreturn mirror 4 is arranged on a predetermined position on the opticalpath X. Therefore, the light from a subject which passed theinterchangeable lens unit 2 is divided into two light beams by a mainmirror 4 a of the quick return mirror 4. The reflected light beam is ledto the viewfinder optical system 19. The transmitted light beam isreflected by a sub mirror 4 b arranged on the rear side of the quickreturn mirror 4, and is used as an AF (Automatic Focus) light beam ofthe focus detection unit 5.

The light beam reflected by the main mirror 4 a forms an image on aviewfinder screen 6. The subject image formed on the viewfinder screen 6can be observed from a viewfinder eyepiece window 9 via a pentaprism 7and an eyepiece 8. In this way, in this viewfinder photographing mode, auser can observe a subject image from the viewfinder eyepiece window 9.

When actually photographing, the quick return mirror 4 is flipped to beoutside the optical path X and the shutter unit 10 is opened, and thesubject image is formed on the imaging surface of the imaging sensor 11.As a result, it is possible to obtain a subject image.

Power is supplied to the body microcomputer 12 of the camera body 1, thelens microcomputer 20 of the interchangeable lens unit 2, and variousunits, with the operation of a user pressing the release button 30 halfway down. The body microcomputer 12, the lens microcomputer 20, andvarious units are actuated by the power supply. The body microcomputer12 receives various lens information from the lens microcomputer 20, viathe lens mount 21 and the body mount 23. The lens information is storedin a built-in memory 68 in the body microcomputer 12.

Next, a defocus amount (hereinafter referred to as Df amount) isobtained by the focus detection unit 5, and the Df amount is sent to thebody microcomputer 12. The focus lens group 25 is driven according tothe Df amount. More specifically, a drive command of the focus lensgroup 25 is sent to the lens microcomputer 20 from the bodymicrocomputer 12. The focus lens group 25 is driven by only the Dfamount by the lens microcomputer 20 via the focus control unit 26. TheDf amount becomes smaller if the focus detection and the drive of thefocus lens group 25 are repeated. When the Df amount became equal to orbelow a predetermined amount, the body microcomputer 12 determines thatit is focused, and stops the drive of the focus lens group 25.

After that, if the release button 30 is pressed all the way down, anaperture adjustment command is sent from the body microcomputer 12 tothe lens microcomputer 20. At this time, for example, based on theoutput from a photometric sensor which is not shown in the figure, theaperture value is calculated by the body microcomputer 12. The openingdegree of the aperture of the aperture unit 28 is adjusted by the lensmicrocomputer 20 via the aperture control unit 27.

Simultaneously with the aperture adjustment, a command for retractingthe quick return mirror 4 from the optical path X is sent from the bodymicrocomputer 12 to the quick return mirror control unit 43. Afterretraction is completed, the imaging sensor 11 is driven by the imagingsensor control unit 13, and the shutter unit 10 is driven by the shuttercontrol unit 14. The opened state of the shutter unit 10 is kept and theimaging sensor 11 is exposed by only the time of the shutter speedcalculated based on the output from the photometric sensor not shown inthe figure by the shutter control unit 14.

After exposure is completed, a predetermined image processing isperformed on the image signal outputted from the imaging sensor 11, andthe image photographed is displayed on the liquid crystal displaymonitor 16. In addition, the image data is recorded in a memory mediavia the image recording unit 18. After exposure is completed, the quickreturn mirror 4 and the shutter unit 10 are reset to the initialpositions. A command to reset the aperture unit 28 to the openedposition is sent from the body microcomputer 12 to the lensmicrocomputer 20. A reset command reaches each unit from the lensmicrocomputer 20. After reset is completed, reset completion informationis sent to the body microcomputer 12 from the lens microcomputer 20. Ifthe reset completion information from the lens microcomputer 20 isreceived and a series of processes after exposure is completed, the bodymicrocomputer 12 confirms that the release button 30 is not beingpressed, and the photographing sequence ends.

2.2: Monitor Photographing Mode

As shown in FIG. 11, when photographing in the monitor photographingmode, a photographing mode switching button 75 is operated, and thephotographing mode changes to the monitor photographing mode. Morespecifically, the quick return mirror drive motor 44 drives the quickreturn mirror 4 by the quick return mirror control unit 43, and thequick return mirror 4 retracts outside the optical path X. As a result,the subject image formed by the imaging optical system L incident on theimaging sensor 11. An image signal is outputted from the imaging sensor11, and after a predetermined image processing is performed, the imagephotographed is displayed on the liquid crystal display monitor 16. Inthis way, in the monitor photographing mode, by displaying a real-timeimage of the subject on the liquid crystal display monitor 16, a usercan observe a subject without peering through the viewfinder eyepiecewindow 9.

If a user presses the release button 30 half way down, same as theviewfinder photographing mode, the focus adjustment and the apertureadjustment are preformed. In the case of the monitor photographing mode,when detecting the focus, the quick return mirror drive motor 44 isdriven by the quick return mirror control unit 43, and the quick returnmirror 4 is returned to a predetermined position on the optical path X.The Df amount is obtained by the focus detection unit 5, and the focuslens group 25 is driven according to the Df amount. The Df amountbecomes smaller if the focus detection and the drive of the focus lensgroup 25 are repeated. When the Df amount became equal to or below apredetermined amount, the body microcomputer 12 determines that it isfocused, and makes the focus control unit 26 stop the drive of the focuslens group 25.

The photographing operation when the release button 30 is pressed allthe way down is the same as the case with the viewfinder photographingmode described previously. After exposure is completed, the quick returnmirror 4 is kept in a state of being retracted from the optical path X.By doing so, it is possible to continue with the monitor photographingmode.

If the photographing mode switching button 75 is operated, the monitorphotographing mode is terminated, and it is switched to the viewfinderphotographing mode. In this case, the quick return mirror 4 is returnedto a predetermined position on the optical path X. In addition, even inthe case that the power of the camera system 100 is switched to OFF, thequick return mirror 4 is returned to the predetermined position on theoptical path X.

In this way, in this camera system 100, since it is possible to use themonitor photographing mode, it becomes extremely easy for a beginner whois inexperienced with the photographing of a digital camera to use thecamera.

2.3: Selection of the Exposure Setting Mode

The camera system 100 includes a program photographing mode, a shutterspeed priority photographing mode, an aperture priority mode, and amanual photographing mode, as the exposure setting modes. The programphotographing mode is a mode which performs exposure settingautomatically with respect to a normal photographing region. The shutterspeed priority mode is a mode in which the shutter speed is setmanually. The aperture priority mode is a mode in which the aperturevalue is set manually. The manual photographing mode is a mode in whichboth the shutter speed and the aperture value are set manually.

These four exposure setting modes can be selected through the aperturering 40 and the shutter speed setting dial 31. More specifically, forexample, the program photographing mode is selected, if the shutterspeed is set to automatic through the shutter speed setting dial 31, inthe state in which the character “A” on the aperture ring 40 matches theindex 33. The shutter speed priority photographing mode is selected, ifthe shutter speed is set to manual through the shutter speed settingdial 31, in the state in which the character “A” on the aperture ring 40matches the index 33. The aperture priority photographing mode isselected, if the shutter speed is set to automatic through the shutterspeed setting dial 31, in the state in which one of any of thecharacters “2” to “11” on the aperture ring 40 matches the index 33. Themanual photographing mode is selected, if the shutter speed is set tomanual through the shutter speed setting dial 31, in the state in whichone of any of the characters “2” to “11” on the aperture ring 40 matchesthe index 33.

Below, out of the four exposure setting modes, the program photographingmode and the shutter speed priority photographing mode are collectivelycalled the automatic aperture mode. Out of the four exposure settingmodes, the aperture priority photographing mode and the manualphotographing mode are collectively called the manual aperture mode.

2.4: Automatic Aperture Mode

The aperture linear sensor 41 outputs a signal according to therotational angle of the aperture ring 40 to the aperture control unit27. The aperture control unit 27 determines that the exposure settingmode is the automatic aperture mode based on the signal received fromthe aperture linear sensor 41, if the release button 30 is beingoperated, and if the character “A” on the aperture ring 40 matches theindex 33. The result determined at the aperture control unit 27 is sentto the lens microcomputer 20 and the body microcomputer 12. At thistime, the transmission to the body microcomputer 12 is, for example,performed via inter-microcomputer communication between the lensmicrocomputer 20 and the body microcomputer 12.

The shutter speed setting dial 31 outputs a signal according to therotational angle to the body microcomputer 12. The body microcomputer 12determines that the exposure setting mode is the automatic aperture modebased on the determined result received from the aperture control unit27 and the signal from the shutter speed setting dial 31.

A command is sent from the body microcomputer 12 to the digital signalprocessing unit 53, and an image signal is sent to the bodymicrocomputer 12 at a predetermined timing from the digital signalprocessing unit 53. An exposure value is calculated by the bodymicrocomputer 12 based on the image signal sent from the digital signalprocessing unit 53. If the exposure setting mode is the programphotographing mode, an appropriate combination of an aperture value anda shutter speed from the adjustable aperture values and the shutterspeeds is decided by the body microcomputer 12. If the exposure settingmode is the shutter speed priority photographing mode, an appropriateaperture value for the set shutter speed is calculated by the bodymicrocomputer 12.

A control signal is generated by the body microcomputer 12 based on thecalculated result. This control signal is sent to the aperture controlunit 27 from the body microcomputer 12 via the lens microcomputer 20. Ifthe exposure setting mode is the program photographing mode, the controlsignal based on the shutter speed which is calculated is sent to theshutter control unit 14 from the body microcomputer 12. If the exposuresetting mode is the shutter speed priority photographing mode, theshutter speed set through the shutter speed setting dial 31 is sent tothe shutter control unit 14 from the body microcomputer 12.

Simultaneously with this, a control signal is sent to the imagedisplaying control unit 15 from the body microcomputer 12. The imagedisplaying control unit 15 drives the liquid crystal display monitor 16based on this control signal. More specifically, if the exposure settingmode is the program photographing mode, the information that theexposure setting mode is the program photographing mode is displayed onthe liquid crystal display monitor 16 by the image displaying controlunit 15. If the exposure setting mode is the shutter speed prioritymode, the information that the exposure setting mode is the shutterspeed priority mode is displayed on the liquid crystal display monitor16 by the image displaying control unit 15.

A drive signal for driving the aperture drive motor 28 b is generated bythe aperture control unit 27, based on a control signal from the lensmicrocomputer 20. The aperture drive motor 28 b is driven based on thisdrive signal, and the aperture blade of the aperture unit 28 is drivenby the aperture drive motor 28 b.

A drive signal for driving the shutter drive motor 10 a is generated bythe shutter control unit 14 based on a control signal from the bodymicrocomputer 12. The shutter drive motor 10 a is driven based on thisdrive signal, and the shutter unit 10 is driven by the shutter drivemotor 10 a.

The exposure setting according to the automatic aperture mode in thecamera system 100 is performed as described above. The operations aboveare executed instantaneously, after the release button 30 is operated.

When photographing ends, a control signal is sent to the image recordingcontrol unit 17 from the body microcomputer 12. As a result, an imagesignal is recorded in an internal memory and/or a recording media by theimage recording unit 18, based on a command from the image recordingcontrol unit 17.

If the exposure setting mode is the program setting mode, theinformation that the exposure setting mode is the program photographingmode is recorded in the internal memory and/or a recording media withthe image signal, based on a command from the image recording controlunit 17. If the exposure setting mode is the shutter priority mode, theinformation that the exposure setting mode is the shutter speed prioritymode is recorded in the internal memory and/or the recording media withthe image signal, based on a command from the image recording controlunit 17.

2.5: Manual Aperture Mode

If a character of any of the characters “2” to “11” on the aperture ring40 matches the index 33, and if the release button 30 is operated, theaperture control unit 27 determines that the exposure setting mode isthe manual aperture mode, based on the signal received from the aperturelinear sensor 41. The determined result at the aperture control unit 27is sent to the lens microcomputer 20.

The shutter speed setting dial 31 outputs a signal according to therotational angle to the body microcomputer 12. The exposure setting modebeing the manual aperture mode is determined by the body microcomputer12 based on the determined result received from the aperture controlunit 27 and the signal from the shutter speed setting dial 31.

The lens microcomputer 20 requests the aperture control unit 27 for theaperture value information detected from the rotational angle of theaperture ring 40. The aperture value information detected from therotational angle of the aperture ring 40 is sent to the lensmicrocomputer 20 and the body microcomputer 12 from the aperture controlunit 27, based on the command from the lens microcomputer 20. If theexposure setting mode is the aperture priority photographing mode, acommand is sent to the digital signal processing unit 53 from the bodymicrocomputer 12, and an image signal is sent to the body microcomputer12 from the digital signal processing unit 53 at a predetermined timing.

If the exposure setting mode is the aperture priority photographingmode, the shutter speed is calculated by the body microcomputer 12 basedon the image signal. If the exposure setting mode is the aperturepriority photographing mode, an appropriate shutter speed is calculatedby the body microcomputer 12 for the detected aperture value. If theexposure setting mode is the aperture priority photographing mode, acontrol signal is generated by the body microcomputer 12 based on thecalculated result. If the exposure setting mode is the aperture priorityphotographing mode, the control signal based on the calculated shutterspeed is sent to the shutter control unit 14 by the body microcomputer12. If the exposure setting mode is the manual photographing mode, theshutter speed set through the shutter speed setting dial 31 is sent tothe shutter control unit 14 by the body microcomputer 12.

Simultaneously with this, a control signal is sent to the imagedisplaying control unit 15 from the body microcomputer 12. The imagedisplaying control unit 15 drives the liquid crystal display monitor 16based on this control signal. More specifically, if the exposure settingmode is the aperture priority photographing mode, the information thatthe exposure setting mode is the aperture priority photographing mode isdisplayed on the liquid crystal display monitor 16 by the imagedisplaying control unit 15. If the exposure setting mode is the manualphotographing mode, the information that the exposure setting mode isthe manual photographing mode is displayed on the liquid crystal displaymonitor 16 by the image displaying control unit 15.

A drive signal for driving the aperture drive motor 28 b is generated bythe aperture control unit 27, based on a control signal from the lensmicrocomputer 20. Based on this drive signal, the aperture drive motor28 b is driven, and the aperture blade of the aperture unit 28 is drivenby the aperture drive motor 28 b.

A drive signal for driving the shutter drive motor 10 a is generated bythe shutter control unit 14, based on a control signal from the bodymicrocomputer 12. The shutter drive motor 10 a is driven based on thisdrive signal, and the shutter unit 10 is driven by the shutter drivemotor 10 a.

The exposure setting according to the manual aperture mode in the camerasystem 100 is performed as described above. The operations above areexecuted instantaneously, after the release button 30 is operated.

When photographing ends, a control signal is sent to the image recordingcontrol unit 17 from the body microcomputer 12. As a result, an imagesignal is recorded in an internal memory and/or a recording media by theimage recording unit 18, based on a command of the image recordingcontrol unit 17.

If the exposure setting mode is the aperture priority mode, theinformation that the exposure setting mode is the aperture priority modeis recorded in the internal memory and/or the recording media with theimage signal by the image recording unit 18, based on a command from theimage recording control unit 17. If the exposure setting mode is themanual photographing mode, the information that the exposure settingmode is the manual photographing mode is recorded in the internal memoryand/or the recording media by the image recording unit 18 with the imagesignal, based on a command from the image recording control unit 17.

3: Depth of Field Reviewing Mode

Next, a depth of field reviewing mode when photographing will bedescribed.

3.1: Summary of the Depth of Field Reviewing Mode

In the depth of field reviewing mode, the depth of field is checked viathe liquid crystal display monitor 16. More specifically, for example,with the viewfinder photographing mode, if the depth of field reviewingmode button 76 is pressed, the photographing mode automatically changesto the monitor photographing mode. As a result, a real-time imagecorresponding to the actual aperture value at the aperture unit 28 isdisplayed on the liquid crystal display monitor 16. This allows thedepth of field to be easily checked via the liquid crystal displaymonitor 16.

For example, in this depth of field reviewing mode, if the aperture ring40 is equipped in the interchangeable lens unit 2, the lensmicrocomputer 20 requests the aperture control unit 27 for the aperturevalue information detected based on the rotational angle of the aperturering 40. The aperture value information detected from the rotationalangle of the aperture ring 40 is sent to the lens microcomputer 20 andthe body microcomputer 12 by the aperture control unit 27, based on acommand from the lens microcomputer 20. A drive signal for driving theaperture drive motor 28 b is generated by the aperture control unit 27,based on a control signal from the lens microcomputer 20. The aperturedrive motor 28 b is driven based on this drive signal, and the apertureblade of the aperture unit 28 is driven by the aperture drive motor 28b.

3.2: Specific Operations of the Depth of Field Reviewing Mode

Next, Specific operations in the depth of field reviewing mode will bedescribed using FIGS. 12 and 13. FIG. 12 is a flowchart of the depth offield reviewing mode. FIG. 13A is an example of an actual aperture imagewhen the aperture value is F2. FIG. 13B is an example of an actualaperture image when the aperture value is F8.

As shown in FIG. 12, whether or not the depth of field reviewing modebutton 76 is pressed is determined by the body microcomputer 12 (S1). Ifthe depth of field reviewing mode button 76 is pressed, it changes tothe depth of field reviewing mode (S2). As shown in FIG. 11, in thedepth of field reviewing mode, the quick return mirror drive motor 44 isdriven by the quick return mirror control unit 43, and the quick returnmirror 4 retracts to be outside the optical path X. After the retractionof the quick return mirror 4, the operation of the imaging sensor 11starts.

Next, as shown in FIGS. 13A and 13B, a real-time image obtained by theimaging sensor 11 is displayed on the liquid crystal display monitor 16,based on a command from the image displaying control unit 15 (S3). If auser operates the aperture ring 40, the aperture information is detectedbased on the rotational angle of the aperture ring 40 by the aperturecontrol unit 27, based on a command from the lens microcomputer 20 (S4,S5). A drive signal for driving the aperture drive motor 28 b isgenerated by the aperture control unit 27 based on a control signal fromthe lens microcomputer 20, and the aperture blade of the aperture unit28 is driven by the aperture drive motor 28 b (S6). As a result, theaperture value of the imaging optical system L is changed to theaperture value set by the aperture ring 40. For example, if the aperturevalue set by the aperture ring 40 is F8, as shown in FIGS. 13A and 13Bfor example, a real-time image with an aperture value being F8 isdisplayed on the liquid crystal display monitor 16. At this time, forexample, the aperture value F8 is displayed on the upper right hand sideof the image on the liquid crystal display monitor 16.

Here, the actual aperture image displayed on the liquid crystal displaymonitor 16 will be described. With an actual aperture image, the depthof field and the brightness change according to the aperture value. Forexample, as shown in FIG. 13A, if the aperture value is F2, an image inwhich the depth of field is shallow with a background that is out offocus compared to the image of the figure captured in the middle isdisplayed. On the other hand, if the aperture value is F8, as shown inFIG. 13B, an image in which the depth of field is comparatively deepwith the figure in the middle and the background focused compared to thecase in which the aperture value is F2 is displayed.

However, normally, with an image in which the aperture value is F8, theamount of light incident on the imaging sensor 11 within a fixed time islittle, compared to the case in which the aperture value is F2.Therefore, compared to an image in which the aperture value is F2, withan image in which the aperture value is F8, the image displayed on theliquid crystal display monitor 16 becomes dark, and it is difficult forthe user to see it.

Consequently, in this camera system 100, a gain alteration treatment(gain up) on the actual aperture image is performed by the AGC unit 59of the analog signal processing unit 51 described previously, so that itis displayed with an optimum brightness on the liquid crystal displaymonitor 16. More specifically, the analog signal of the actual apertureimage is amplified by the AGC unit 59 according to the aperture value.As a result, it is possible for the brightness of the two images shownin FIGS. 13( a) and (b) to be approximately the same, regardless of theaperture values.

In this way, in this camera system 100, it is possible to brightlydisplay an actual aperture image that becomes dark, according to theaperture value. By doing so, without being affected by the difference inthe brightness, the user can easily check the depth of field of animage.

Whether the depth of field reviewing mode button 76 is OFF or not isdetermined by the body microcomputer 12, and Steps S3 to S6 arerepeated, if it is not OFF (S7). As a result, a real-time imagecorresponding to the aperture value set on the aperture ring 40 isdisplayed on the liquid crystal display monitor 16, and it is possibleto easily check the depth of field when photographing via the liquidcrystal display monitor 16.

On the other hand, if the depth of field reviewing mode button 76 isswitched to OFF, the quick return mirror 4 is returned to apredetermined position on the optical path X, and the depth of fieldreviewing mode ends (S8).

4: Advantages

In this camera system 100, the analog signal of an actual aperture imageis amplified according to the set aperture value by the AGC unit 59 ofthe analog signal processing unit 51. Therefore, even if the aperturevalue is small and that the amount of light incident on the imagingsensor 11 within a fixed time is little, the actual aperture imagedisplayed on the liquid crystal display monitor 16 is bright, regardlessof the aperture value. As a result, the user can easily check the depthof field of images without being affected by the difference in thebrightness of the images due to the difference in the aperture values.

Second Embodiment

In the above described embodiment, only one image is displayed on theliquid crystal display monitor 16. However, it is also possible to havea configuration in which images obtained with different aperture valuesare displayed side by side on the liquid crystal display monitor 16.Here, specific operations of the depth of field reviewing mode accordingto a second embodiment will be described using FIGS. 14 to 16. FIGS. 14and 15 are flowcharts of the depth of field reviewing mode according tothe second embodiment. FIG. 16 is a displaying example of the liquidcrystal display monitor 16. In addition, the configuration in the secondembodiment is basically the same as the configuration in the firstembodiment. Therefore, the description thereof is omitted, and portionsthat are different will be described mainly.

As shown in FIG. 14, whether or not the depth of field reviewing modebutton 76 is pressed is determined by the body microcomputer 12 (S11).If the depth of field reviewing mode button 76 is pressed, it is changedto the depth of field reviewing mode (S12). As shown in FIG. 11, in thedepth of field reviewing mode, the quick return mirror drive motor 44 isdriven by the quick return mirror control unit 43, and the quick returnmirror 4 retracts outside of the optical path X. After the retraction ofthe quick return mirror 4, the operation of the imaging sensor 11starts.

Here, an image as the standard for comparing the depths of field isautomatically obtained. More specifically, as shown in FIG. 16, aportion of an image with aperture value of F2 obtained by the imagingsensor 11 is displayed as standard image A on the left side of theliquid crystal display monitor 16 based on a command from the imagedisplaying control unit 15 (S13). The aperture value at this time is,for example, the standard aperture value set in advance by the bodymicrocomputer 12. This standard aperture value is the brightest aperturevalue (aperture in the most opened state) in the interchangeable lensunit 2, and the depth of field is the shallowest. Therefore, thestandard image A is the image in which the background is out of focuswith respect to the figure captured in the middle. The standard image Ais temporarily stored by the buffer memory 54, and the state of it beingdisplayed on the liquid crystal display monitor 16 by the imagedisplaying control unit 15 is maintained.

Next, if the user operates the aperture ring 40, the apertureinformation based on the rotational angle of the aperture ring 40 isdetected by the aperture control unit 27, based on a command from thelens microcomputer 20 (S14, S15). A drive signal for driving theaperture drive motor 28 b is generated by the aperture control unit 27based on a control signal from the lens microcomputer 20, and theaperture blade of the aperture unit 28 is driven by the aperture drivemotor 28 b (S16). As a result, the aperture value of the imaging opticalsystem L is changed to the aperture value (set aperture value) set bythe aperture ring 40. For example, if the set aperture value by theaperture ring 40 is F8, the real-time image of F8 set at the aperturering 40 is displayed as a comparative image B on the right side of theliquid crystal display monitor 16 (S17). At this time, same as the abovedescribed first embodiment, the image signal of the comparative image Bis gained up by the AGC unit 59. Since the comparative image B is animage with an aperture value of F8, it is an image with a depth of fieldthat is deep, with both the figure in the middle and the backgroundfocused, compared to the standard image A.

Here, if the release button 30 is being pressed all the way down, thephotographing mode changes to the action mode (S18). More specifically,as shown in FIG. 15, the quick return mirror 4 is returned to apredetermined position on the optical path X, and the focus operation isperformed (S21, S22). Next, the quick return mirror 4 retracts outsidethe optical path X (S23), and the aperture value is adjusted to thestandard aperture value F2 (S24). More specifically, the aperture bladeof the aperture unit 28 is driven so that the aperture value becomes theset aperture value F2, and an image with an aperture value of F2 isphotographed (S25).

Next, the aperture value is set to the set aperture value F8 (S26). Morespecifically, the aperture blade of the aperture unit 28 is driven sothat the aperture value becomes F8, and an image with an aperture valueof F8 is photographed (S27). Through these steps, two images withdifferent depths of field are continuously taken, and the two images arerecorded in the internal memory and/or the recording media, based on acommand of the image recording control unit 17 (S28). When this actionmode ends, the depth of field reviewing mode, from Step S13 shown inFIG. 14, is restarted.

On the other hand, if the release button 30 is not pressed all the waydown, whether or not the depth of field reviewing mode button 76 is OFFis determined by the body microcomputer 12 (S18, S19). If it is not OFF,Steps 13 to 18 are repeated (S19). If the depth of field reviewing modebutton 76 is switched to OFF, the quick return mirror 4 is returned to apredetermined position on the optical path X, and the depth of fieldreviewing mode ends (S20).

In this way, in the depth of field reviewing mode of this embodiment,since the standard image A and the comparative image B are displayedside by side on the liquid crystal display monitor 16, it is possible tocompare images with different depths of field side by side. As a result,it becomes easy for the user to grasp the difference in the images dueto the difference in the aperture values.

In addition to that, same as the above described first embodiment, theimage signal of the comparative image B is gained up by the AGC unit 59.Therefore, it is possible to have the brightness of the standard image Aand the comparative image B to be approximately the same, regardless ofthe aperture values. By doing so, when comparing a plurality of imagesside by side, the user can easily check the depths of field of theimages, without being affected by the difference in the brightness.

In addition, in the action mode, it is possible to continuously takeimages with different depths of field, while looking at imagescorresponding to the aperture values at the time of actuallyphotographing, or the actual aperture images. Therefore, it is possibleto simplify the setting of photographing conditions and the like, and itis possible to expand the photographing range of the user.

Other Embodiments

The specific configurations of the present invention are not limited tothose in the embodiments described previously, and various modificationsand corrections are possible within the range not deviating from thesubstance of the invention.

(1)

In the above described second embodiment, two images with differentdepths of field are displayed side by side on the liquid crystal displaymonitor 16. However, the displaying format of the images is not limitedto that in the embodiment described above. For example, the case that,as shown in FIG. 17, in the display region of the display monitor 16,one image is divided into left and right in the middle of the figure,and the left half of the standard image A, which is temporarily stored,with the standard aperture value of F2 is displayed on the left side ofthe display region, and the right half of the comparative image B withthe set aperture value of F8 is displayed on the right side of thedisplay region, as the live image, is also possible. Same as the case inthe second embodiment described above, the comparative image B is thereal-time image obtained with the set aperture value.

In addition, in the above described second embodiment, two images aredisplayed side by side on the liquid crystal display monitor 16, and twoimages are continuously taken in the action mode. However, the number ofimages displayed and the images continuously taken is not limited totwo, and it may be three or more.

In addition, photographing is not limited to continuous shooting, andeither the standard image A or the comparative image B may bephotographed.

In addition, the standard aperture value and the set aperture value arenot limited to F2 and F8 described above.

(2)

In the embodiment described above, the aperture value is changed usingthe aperture ring 40 equipped in the interchangeable lens unit 2.However, it is also possible to have a case in which the aperture ring40 is not equipped in the interchangeable lens unit 2. In this case, forexample, the aperture value is changed using a dial and the likeequipped in the camera body 1. The dial equipped in the camera body 1does not have to be a dial exclusively used for setting the aperturevalue. For example, other than setting the aperture value, it mayinclude other functions.

(3)

In the embodiment described above, the image obtained by the imagingsensor 11 is displayed on the liquid crystal display monitor 16.However, instead of the imaging sensor 11, it may be configured withanother imaging sensor arranged on the viewfinder optical system 19, andthe image may be obtained by this imaging sensor. In this case, it isnot necessary to retract the quick return mirror outside the opticalpath X.

In addition, the configuration and the arrangement of the quick returnmirror 4 and the viewfinder optical system 19 are not limited to thosein the first and the second embodiments described above.

(4)

In the embodiment described above, the photographing mode is changed tothe depth of field reviewing mode if the depth of field reviewing modebutton 76 is pressed once, and the depth of field reviewing mode iscancelled if it is pressed again. However, the configuration may be tohave the depth of field reviewing mode continue only while the depth offield reviewing mode button 76 is being pressed.

(5)

In the embodiment described above, the focus detection system is thephase difference detection system used the focus detection unit 5.However, the focus detection system may be, for example, a contrastdetection system used the imaging sensor 11. In this case, for example,processes in Steps S21 and S23 shown in FIG. 15 become unnecessary, andit is possible to reduce the focus operation time.

In addition, in the embodiment described above, the case in which imagescorresponding to two aperture values are displayed on the liquid crystaldisplay monitor 16 was described. However, it is not limited to this.For example, images corresponding to a plurality, three or more, ofaperture values may be displayed as multi-screens on the liquid crystaldisplay monitor 16. At this time, the image which corresponds to theaperture value when the aperture is in the opened state may beconstantly displayed on a specific display region on the liquid crystaldisplay monitor 16, and a plurality of images which correspond toaperture values other than the aperture value when the aperture is inthe opened state may be displayed in other display regions respectively.

(6)

In the embodiment described above, the gain up treatment is performed bythe AGC unit 59 of the analog signal processing unit 51. However, it isalso possible to adjust the brightness of an image according to theaperture value by increasing the sensitivity of the imaging sensor 11through the analog signal processing unit 51 and the like. In addition,a treatment equivalent to the gain up treatment may be performed by aportion other than the analog signal processing unit 51.

(7)

In the embodiment described above, a camera system using a single-lensreflex digital camera as an example is described. However, it is alsopossible to apply this camera system to a digital camera other than thesingle-lens reflex type, if it includes an aperture value alterationfunction.

(8)

The coordinate axes and the directions used in the description above arenot for limiting the state of use of the camera system 100.

Additional Statement

The present invention can also be expressed in the following way.

1: Content of the Additional Statement Additional Statement 1

An imaging device including an observation optical system having amovable reflecting mirror arranged between an imaging optical system andan image pickup device, and observes a light reflected by the reflectingmirror, the imaging device comprising:

a reflecting mirror drive unit for driving the reflecting mirror;

a first photographing mode in which the reflecting mirror is driven to afirst state so that a light passed through the imaging optical system isreflected by the reflecting mirror and led to the observation opticalsystem, and performs photographing;

a second photographing mode in which the reflecting mirror is driven toa second state so that a light passed through the imaging optical systemis led to the image pickup device, and performs photographing;

an image processing unit for changing the gain on a captured image;

an image displaying unit for displaying the captured image; and

a preview operation unit in which, by being operated, the imagingoptical system is controlled to a real aperture state and changes to thesecond photographing mode, and along with this, the captured image isdisplayed on the displaying unit in a state where the gain thereof isenlarged by the image processing unit.

Additional Statement 2

An imaging device including an observation optical system having amovable reflecting mirror arranged between an imaging optical system andan image pickup device, and observes a light reflected by the reflectingmirror, the imaging device comprising:

a reflecting mirror drive unit for driving the reflecting mirror;

a first photographing mode in which the reflecting mirror is driven to afirst state so that a light passed through the imaging optical system isreflected by the reflecting mirror and led to the observation opticalsystem, and performs photographing;

a second photographing mode in which the reflecting mirror is driven toa second state so that a light passed through the imaging optical systemis led to the image pickup device, and performs photographing;

an image processing unit for changing the gain on a captured image;

an image displaying unit for displaying the captured image;

a preview operation unit in which, by being operated, the imagingoptical system is controlled to a first aperture state and changes tothe second photographing mode, and along with this, the captured imageis displayed on the displaying unit in a state where the gain thereof isenlarged by the image processing unit;

an aperture alteration unit for changing the aperture value of theoptical system; and

an image displaying control unit for displaying an image data in asecond real aperture state different from the first real aperture stateby operating the aperture alteration unit in a state where the previewoperation unit is operated, simultaneously with an image data in thefirst aperture state, on the image displaying unit.

Additional Statement 3

The imaging device according to Additional Statement 2, comprising acaptured image in the first real aperture state, and an image recordingunit for recording the captured image in the second real aperture state.

2: Description of the Additional Statements

The invention described in Additional Statement 1 is an imaging deviceincluding an observation optical system having a movable reflectingmirror arranged between an imaging optical system and an image pickupdevice, and observes a light reflected by the reflecting mirror. Theimaging device includes a reflecting mirror drive unit for driving thereflecting mirror; a first photographing mode in which the reflectingmirror is driven to a first state so that a light passed through theimaging optical system is reflected by the reflecting mirror and led tothe observation optical system, and photographing is performed; a secondphotographing mode in which the reflecting mirror to a second state sothat a light passed through the imaging optical system is led to theimage pickup device, and photographing is performed; an image processingunit for changing the gain on a captured image; an image displaying unitfor displaying the captured image; and a preview operation unit inwhich, by being operated, the imaging optical system is controlled to areal aperture state and changes to the second photographing mode, andalong with this, the captured image is displayed on the displaying unitin a state where the gain thereof is enlarged by the image processingunit.

The invention described in Additional Statement 2 is an imaging devicecomprising a reflecting mirror drive unit for driving a reflectingmirror; a first photographing mode in which the reflecting mirror isdriven to a first state so that a light passed through an imagingoptical system is reflected by the reflecting mirror and led to anobservation optical system, and photographing is performed; a secondphotographing mode in which driving the reflecting mirror to a secondstate so that a light passed through the imaging optical system is ledto an image pickup device, and performs photographing; an imageprocessing unit for changing the gain on a captured image; an imagedisplaying unit for displaying the captured image; a preview operationunit in which, by being operated, the imaging optical system iscontrolled to a first aperture state and changes to the secondphotographing mode, and along with this, the captured image is displayedon the displaying unit in a state where the gain thereof is enlarged bythe image processing unit; an aperture alteration unit for changing theaperture value of the optical system; and an image displaying controlunit for displaying an image data in a second real aperture statedifferent from the first real aperture state by operating the aperturealteration unit in a state where the preview operation unit is operated,simultaneously with an image data in the first aperture state, on theimage displaying unit.

The invention described in Additional Statement 3 is an imaging devicecharacterized in comprising a captured image in a first real aperturestate, and an image recording unit for recording the captured image in asecond real aperture state.

INDUSTRIAL APPLICABILITY

In the camera system according to the present invention, it is possibleto display even images with different aperture values to approximatelythe same brightness. Therefore, it is useful in the field of the digitalcamera comprising an aperture value alteration function.

1. A camera system for photographing a subject, the camera systemcomprising: an imaging optical system configured to form an opticalimage of the subject; an imaging unit configured to convert the opticalimage into an image signal, and obtaining an image of the subject; amovable reflecting mirror arranged between the imaging optical systemand the imaging unit; an observation optical system through which alight reflected by the reflecting mirror is observed; a reflectingmirror drive unit configured to drive the reflecting mirror; an apertureadjustment unit which can adjust an aperture value of the imagingoptical system; a display unit configured to display the image; an imageadjustment unit configured to adjust the brightness of the imagedisplayed on the display unit according to the aperture value; and apreview operation unit configured to be operated, wherein based onoperating the preview operation unit, the aperture adjustment unitchanges an aperture value of the imaging optical system to a setaperture value, the reflecting mirror drive unit drives the reflectingmirror outside an optical path formed between the imaging optical systemand the image pickup device, and the display unit displays the imageobtained by the imaging unit.
 2. The camera system according to claim 1,wherein when the image is displayed on the display unit based onoperating the preview operation unit, the image adjustment unitamplifies the image signal according to the aperture value.
 3. Thecamera system according to claim 2, wherein the image adjustment unitamplifies the image signal based on information on the relationshipbetween the aperture value and the amplification factor of the imagesignal.
 4. The camera system according to claim 2, further comprising anaperture value input unit to which the aperture value can be input,wherein, the display unit configured to display a standard imageobtained with a standard aperture value set in advance, and acomparative image obtained with a set aperture value set in the aperturevalue input unit, side by side, based on operating the preview operationunit.
 5. The camera system according to claim 4, further comprising: anoperation unit to which information can be input from the outside; andan image recording unit for recording the image, wherein, the standardimage and comparative image are recorded in the image recording unitbased on information inputted from the operation unit.
 6. The camerasystem according to claim 1, wherein the image displayed on the displayunit based on operating the preview operation unit is a real-time image.7. The camera system according to claim 4, wherein when the aperturevalue for obtaining the standard image differs from the aperture valuefor obtaining the comparative image, the image adjustment unit sets theamplification factor for an image signal of the standard image and theamplification factor for an image signal of the comparative image to bedifferent from each other.